Hi, When using a head-unit without pre-outs and looking at taking a high level feed from the head-unit to the amplifier which is the better option and why? 1. High level from the speaker cable into the high level input of the amp (assuming it has one) so the amp reduces the signal to a low level input. 2. High level from the speaker cable using something like this lead? Do they work in the same way ie are the electronics inside the amp the same as whats in the lead? Is there a discernible difference in terms of audio quality or interference between the two? Thank you. Stu
There are mainly two ways to take a high level signal and convert it to low level. The first is a transformer coupling and the other is capacitor coupling. Both have advantages and disadvantages. Transformer coupling is good because it isolates the HU from the amp. It is very unlikely that noise can be transfered across the coil. However, a transformer is not a linear device. The audio is slightly distorted. The audio quality is degraded. Cap coupling does not isolate the HU and the amp. Noise can be transfered. But the capacitor (regardless of the value) is a crossover. It blocks lower frequency. No matter what value we choose we will lose a little of the lower frequencies. Because the radio has no RCA's, I'm going to assume that it is of a lower quality. So its audio output is not that good. Adding an amp to a radio like that will not improve the sound quality of your system, regardless of the LOC you choose. Not all LOCs are created equal, some are better than others. So, my opinion, save your money. If the amp has a high level input, use it
Thanks for the reply. This was a general question about considering on how to improve factory installs on a budget and with a selection of old kit from previous installations. For example: hooking up the factory HU to a 4 channel amp which would allow the front cabin speakers to be filtered it the amp has built in high/low pass filters and the rear channels to be bridged and power a sub. I accept that the output from the HU will not be of amazing quality (though some modern units are much better than I would have thought) but surely thats a better option than leaving it standard? I have a 4 channel amp, small boxed sub and appropriate wiring sat in my garage. What I don't have is the time/money to start spending hundreds on a new HU and speakers so was looking at what I could do with what I had. Maybe I should start a new thread listing what parts I have and see what advice forum members can offer on the best way to match them up. Stu.
If your only choice is the factory radio then an amp would be an improvement over doing nothing at all. Also replace the factory speakers. One thing I have done with the factory radio is the JL Audio Clean sweep. Something to consider. But if I'm given the choise between an LOC and an amps high level input, I'll use the amps high level input.
